Metamath Proof Explorer


Theorem bnj864

Description: Technical lemma for bnj69 . This lemma may no longer be used or have become an indirect lemma of the theorem in question (i.e. a lemma of a lemma... of the theorem). (Contributed by Jonathan Ben-Naim, 3-Jun-2011) (New usage is discouraged.)

Ref Expression
Hypotheses bnj864.1 ( 𝜑 ↔ ( 𝑓 ‘ ∅ ) = pred ( 𝑋 , 𝐴 , 𝑅 ) )
bnj864.2 ( 𝜓 ↔ ∀ 𝑖 ∈ ω ( suc 𝑖𝑛 → ( 𝑓 ‘ suc 𝑖 ) = 𝑦 ∈ ( 𝑓𝑖 ) pred ( 𝑦 , 𝐴 , 𝑅 ) ) )
bnj864.3 𝐷 = ( ω ∖ { ∅ } )
bnj864.4 ( 𝜒 ↔ ( 𝑅 FrSe 𝐴𝑋𝐴𝑛𝐷 ) )
bnj864.5 ( 𝜃 ↔ ( 𝑓 Fn 𝑛𝜑𝜓 ) )
Assertion bnj864 ( 𝜒 → ∃! 𝑓 𝜃 )

Proof

Step Hyp Ref Expression
1 bnj864.1 ( 𝜑 ↔ ( 𝑓 ‘ ∅ ) = pred ( 𝑋 , 𝐴 , 𝑅 ) )
2 bnj864.2 ( 𝜓 ↔ ∀ 𝑖 ∈ ω ( suc 𝑖𝑛 → ( 𝑓 ‘ suc 𝑖 ) = 𝑦 ∈ ( 𝑓𝑖 ) pred ( 𝑦 , 𝐴 , 𝑅 ) ) )
3 bnj864.3 𝐷 = ( ω ∖ { ∅ } )
4 bnj864.4 ( 𝜒 ↔ ( 𝑅 FrSe 𝐴𝑋𝐴𝑛𝐷 ) )
5 bnj864.5 ( 𝜃 ↔ ( 𝑓 Fn 𝑛𝜑𝜓 ) )
6 1 2 3 bnj852 ( ( 𝑅 FrSe 𝐴𝑋𝐴 ) → ∀ 𝑛𝐷 ∃! 𝑓 ( 𝑓 Fn 𝑛𝜑𝜓 ) )
7 df-ral ( ∀ 𝑛𝐷 ∃! 𝑓 ( 𝑓 Fn 𝑛𝜑𝜓 ) ↔ ∀ 𝑛 ( 𝑛𝐷 → ∃! 𝑓 ( 𝑓 Fn 𝑛𝜑𝜓 ) ) )
8 7 imbi2i ( ( ( 𝑅 FrSe 𝐴𝑋𝐴 ) → ∀ 𝑛𝐷 ∃! 𝑓 ( 𝑓 Fn 𝑛𝜑𝜓 ) ) ↔ ( ( 𝑅 FrSe 𝐴𝑋𝐴 ) → ∀ 𝑛 ( 𝑛𝐷 → ∃! 𝑓 ( 𝑓 Fn 𝑛𝜑𝜓 ) ) ) )
9 19.21v ( ∀ 𝑛 ( ( 𝑅 FrSe 𝐴𝑋𝐴 ) → ( 𝑛𝐷 → ∃! 𝑓 ( 𝑓 Fn 𝑛𝜑𝜓 ) ) ) ↔ ( ( 𝑅 FrSe 𝐴𝑋𝐴 ) → ∀ 𝑛 ( 𝑛𝐷 → ∃! 𝑓 ( 𝑓 Fn 𝑛𝜑𝜓 ) ) ) )
10 impexp ( ( ( ( 𝑅 FrSe 𝐴𝑋𝐴 ) ∧ 𝑛𝐷 ) → ∃! 𝑓 ( 𝑓 Fn 𝑛𝜑𝜓 ) ) ↔ ( ( 𝑅 FrSe 𝐴𝑋𝐴 ) → ( 𝑛𝐷 → ∃! 𝑓 ( 𝑓 Fn 𝑛𝜑𝜓 ) ) ) )
11 df-3an ( ( 𝑅 FrSe 𝐴𝑋𝐴𝑛𝐷 ) ↔ ( ( 𝑅 FrSe 𝐴𝑋𝐴 ) ∧ 𝑛𝐷 ) )
12 11 bicomi ( ( ( 𝑅 FrSe 𝐴𝑋𝐴 ) ∧ 𝑛𝐷 ) ↔ ( 𝑅 FrSe 𝐴𝑋𝐴𝑛𝐷 ) )
13 12 imbi1i ( ( ( ( 𝑅 FrSe 𝐴𝑋𝐴 ) ∧ 𝑛𝐷 ) → ∃! 𝑓 ( 𝑓 Fn 𝑛𝜑𝜓 ) ) ↔ ( ( 𝑅 FrSe 𝐴𝑋𝐴𝑛𝐷 ) → ∃! 𝑓 ( 𝑓 Fn 𝑛𝜑𝜓 ) ) )
14 10 13 bitr3i ( ( ( 𝑅 FrSe 𝐴𝑋𝐴 ) → ( 𝑛𝐷 → ∃! 𝑓 ( 𝑓 Fn 𝑛𝜑𝜓 ) ) ) ↔ ( ( 𝑅 FrSe 𝐴𝑋𝐴𝑛𝐷 ) → ∃! 𝑓 ( 𝑓 Fn 𝑛𝜑𝜓 ) ) )
15 14 albii ( ∀ 𝑛 ( ( 𝑅 FrSe 𝐴𝑋𝐴 ) → ( 𝑛𝐷 → ∃! 𝑓 ( 𝑓 Fn 𝑛𝜑𝜓 ) ) ) ↔ ∀ 𝑛 ( ( 𝑅 FrSe 𝐴𝑋𝐴𝑛𝐷 ) → ∃! 𝑓 ( 𝑓 Fn 𝑛𝜑𝜓 ) ) )
16 8 9 15 3bitr2i ( ( ( 𝑅 FrSe 𝐴𝑋𝐴 ) → ∀ 𝑛𝐷 ∃! 𝑓 ( 𝑓 Fn 𝑛𝜑𝜓 ) ) ↔ ∀ 𝑛 ( ( 𝑅 FrSe 𝐴𝑋𝐴𝑛𝐷 ) → ∃! 𝑓 ( 𝑓 Fn 𝑛𝜑𝜓 ) ) )
17 6 16 mpbi 𝑛 ( ( 𝑅 FrSe 𝐴𝑋𝐴𝑛𝐷 ) → ∃! 𝑓 ( 𝑓 Fn 𝑛𝜑𝜓 ) )
18 17 spi ( ( 𝑅 FrSe 𝐴𝑋𝐴𝑛𝐷 ) → ∃! 𝑓 ( 𝑓 Fn 𝑛𝜑𝜓 ) )
19 5 eubii ( ∃! 𝑓 𝜃 ↔ ∃! 𝑓 ( 𝑓 Fn 𝑛𝜑𝜓 ) )
20 18 4 19 3imtr4i ( 𝜒 → ∃! 𝑓 𝜃 )